Anthrax in Horses

Anthrax has a high fatality rate in horses, and the disease can also affect humans.

This infographic from the Centers for Disease Control (CDC) shows how anthrax can infect an animal. CDC

Lying dormant in the soil, especially alkaline soil, for many years, anthrax spores can proliferate if ingested, inhaled or enter into wounds or even through insect bites. Ingestion of long-dormant spores occurs following heavy rain that moves spores through the soil onto grazed grasses or during drought conditions when grasses are cropped close to the soil. Ingestion is the most common route for horses to obtain anthrax infection.

Links in articles are part of an Amazon Affiliate program that provides income to support this brand. Links are chosen by our editors.

Bacillus anthracis causes septicemia that rapidly progresses. Anthrax has a high fatality rate within 2-4 days.

Equine business owners can create an Amazon Business Account.

Clinical signs include high fever, breathing difficulty, swelling on the chest and underside of the neck, lethargy, inappetence, bloody diarrhea, colic and seizures.

Anthrax vaccine is recommended only for horses living in areas known to harbor anthrax spores. 

This disease can be spread to humans, so it is a reportable disease through the state’s veterinary animal health department or state veterinarian.


The following is from the AAEP.

The only vaccine currently licensed for use in horses is a live acapsular Sterne strain, spore-form. The vaccine has been shown to be effective; however, vaccination of pregnant mares is not recommended. Adverse reactions to the vaccine have been reported in young and miniature horses. Local swelling may occur at the injection site, most of which resolves within a few days.

Appropriate caution should be used during storage, handling and administration of this live bacterial product. Consult a physician immediately if human exposure to the vaccine occurs through accidental injection, ingestion, or otherwise through the conjunctiva or broken skin.

Antimicrobial drugs should not be given concurrently, as this may interfere with adequate response to the vaccine.

Sign up now for Amazon Prime 30-day Free Trials, a membership program that offers special benefits including: Instantly watch thousands of movies and TV episodes; Borrow Kindle books; Get unlimited FREE two-day shipping (no minimum order size). Learn more.






Oops! We could not locate your form.